What lies beneath

From the depths of the Tasman Sea come some very strange fish. Richard Macey reports.

Vampirism, group sex and stockpiles of deadly weapons have been uncovered by a joint investigation between Australia and New Zealand. It's all been found going on beneath the cover of the Tasman Sea.

For a month last year the research ship Tangaroa trawled the waters, hauling in from two kilometres down weird and well-armed creatures inhabiting undersea mountains whose few dry peaks include Norfolk and Lord Howe islands.

Funded by Australia's National Oceans Office, and involving scientists, government agencies, museums and universities in Australia and New Zealand, the expedition snared 500 fish species and 1300 species of invertebrate now being studied by more than 50 researchers around the world.

"Probably over 100 are new species," said Mark Norman, a senior curator at Museum Victoria. Others have only been seen a few times before.

"The diversity down there is incredibly rich," said Peter Last, a CSIRO scientist. "Animals got stuck there and have turned into new species."

One cup of sand contained 250 species of tiny snails.

Dr Norman named the deep sea angler fish, with its bizarre sex life, as one of the most unusual inhabitants.

"The female is the size of a tennis ball. It has big savage teeth, little nasty pin eyes . . . and a rod lure off the top of its head with a glowing tip to coax in stupid prey." The male "looks like a black jellybean with fins".

When a male finds a female, he bites into her side, never letting go. "He drinks her blood, in return for giving her sperm," Dr Norman said. The flesh of the two fish eventually fuses "and they remain connected, permanently. It's sexual vampirism, with a bit of dwarfism thrown in. They have found females with up to six males attached."

There are fish with tongues covered in teeth and fish with hinged teeth to help get down huge meals.

The Pacific spookfish uses its long snout "like a metal detector" to scan for the electrical impulses of prey buried in the mud.

The dumbo octopus has a pair of flaps to help it glide through the water, making it "look like the cartoon character Dumbo the Flying Elephant".

Giant sea spiders, not spiders at all, have such tiny bodies they keep some organs in their legs.

Dr Norman was also fond of the fangtooth, "one of the most savage-looking of all the deep-sea fishes". Two sharp teeth poking out of its bottom jaw slide into pockets in its head, saving the fish from stabbing itself in the brain.

Dr Last cited an apparently new deep-water batfish as among his favourites found by the Norfanz (Norfolk Island, Australia and New Zealand) expedition: "They walk along the bottom . . . their fins are almost modified into legs and the head comes to a point like a unicorn. It's pretty weird."